Although most times there is a legitimate reason, I do know of a case where a meter went crazy.
A friend called and said their power bill had tripled.
I checked it out and the meter was running pretty fast, so I asked if there had been any changes in the house or A/C (it was summer) and they said no.
A lot of people look at a meter and see the disc spin around fast or slow. The thing forgotten often is to look at the constant of the meter. In USA Kh and in NZ revs/kWh.
For example: A 750 rev/kWh meter runs twice as fast as a 375 rev/kWh meter and four times as fast as a 187.5 meter under the same load.
An on site meter test is likely to be charged for also when it's done by an external test house. We were in that position a few years ago after the POCO contracted everything out. Sometimes for political reasons the POCO waived the charge for the customer.
If a meter gets changed for whatever reason, some customers change useage sometimes too in hope for a refund if a POCO meter was for example within its accuracy but on the + 2% side.
